CKEditor get dialog select item

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/ckeditor/4.2/ckeditor.js"></script>
<textarea id="editor">Hello world!</textarea>

JavaScript

CKEDITOR.dialog.add( 'myDialog', function( editor ) {
	return {
		title: 'My Dialog',
        onOk: function() {   
            this.commitContent();
        },        
		contents: [
			{
				id: 'tab1',
				label: 'First Tab',
				title: 'First Tab',
				elements: [
                    {
                    type: 'html',
                    html: `<div id="myDiv">
                    
  <input type="radio" id="html" name="fav_language" value="HTML">
  <label for="html">HTML</label><br>
  <input type="radio" id="css" name="fav_language" value="CSS">
  <label for="css">CSS</label><br>
  <input type="radio" id="javascript" name="fav_language" value="JavaScript">
  <label for="javascript">JavaScript</label>
  
                    </div>`
                }
				]
			}			
		]
	};
});

CKEDITOR.on( 'instanceCreated', function( ev ) {
    var editor = ev.editor;

    editor.on( 'pluginsLoaded', function() {
        editor.addCommand( 'myDialogCmd', new CKEDITOR.dialogCommand( 'myDialog' ) );
        
        editor.ui.add( 'MyButton', CKEDITOR.UI_BUTTON, {
            label: 'My Dialog',
            command: 'myDialogCmd'
        } );
    } );
} );

CKEDITOR.replace( 'editor', {
    toolbar: [ [ 'MyButton' ] ]
} );